In the area of cyclic mechanical motions, there have been various ways and means for driving an element or device for a small distance at extremely fast operation. The element or device may be a specific part of a mechanism which operates in a repeatable and controlled manner in an application utilizing a concept of magnetic repulsion. Examples of such type mechanism may include a striking mechanism for impression of a character or portion of a character onto a record paper, as used in a high-speed electromechanical printer, a pulsed electromagnetic valve or valve-pump combination for metering of a fluid, as used in the fuel injection system of an internal combustion engine, or an electromagnetic hammer for swaging, staking, riveting or stapling parts, as used in various production machines.
The ways and means used in the prior art have included at least two concepts for translating the forces of a magnetic field into a mechanical force or movement for driving an element or device of a mechanism. One concept utilizes a magnetic field which is applied across a magnetic gap or like discontinuity, wherein a magnetically permeable part is placed or positioned near the discontinuity in a manner to cause a portion of the magnetic flux to pass through the permeable part, and the magnetic field then exerts a force on the permeable part which tends to move the part to close the gap or discontinuity. This concept or principle of operation is applied typically to relays and solenoids. As long as the materials of the various parts involved do not become magnetically saturated, the mechanical force will be directly proportional to the magnetic flux that is common to the magnetic field generator and the moving part, and the mechanical force will always be in a direction which tends to minimize the flux path.
The second concept also utilizes a magnetic field which is applied across a magnetic gap or discontinuity, and a magnetically polarized part is placed or positioned in proximity to this gap, so that some of the magnetic flux will pass through the polarized part. The magnetic field exerts a mechanical force on the polarized part in a direction which tends to align the polarization of the part with the field flux. This second concept or principle of operation is applied typically to motors and bi-directional servomechanisms. So long as the materials of the various parts involved do not become mechanically saturated, the mechanical force will be directly proportional to the magnetic flux that is common to the field generator and the polarized part, and the mechanical force will always be in a direction which tends to align the polarization of the moving part with the field flux.
In the concepts or principles of operation of the prior art mentioned above, the operating parameters are chosen so that none of the materials involved in the magnetic path will become saturated during normal operation. In the first mentioned concept, saturation is avoided because any field in excess of saturation will no longer cause a corresponding increase in the mechanical force, which is the desired end result of this concept. As a consequence, saturation is a wasted effort when using the principles of operation of this concept. In the second mentioned concept, saturation is also avoided because of the wasted effort noted above. Saturation is also avoided when using the second concept because this mode of operation frequently makes use of magnetically reluctant materials for the polarized portion of the magnetic circuit. If this type of polarized material is subjected to saturation, then the polarization could be changed or cancelled and the machine operation likewise changed or inhibited. The use of a solenoid or like electromagnetic device has been common to provide the energy and driving force for moving print hammers in printing operations. The use of magnetic and electromagnetic devices has included different concepts for use in operating or driving the various printing elements, for example, in a high speed printer.
Representative prior art relating to the present invention includes U.S. Pat. No. 2,785,390 issued to J. A. Rajchman on Mar. 12, 1957, which discloses devices using hysteretic characteristics of magnetic and ferroelectric materials wherein information may be shifted from a core to a cell by applying shift pulses to change the direction of magnetization of the core, or to change the direction of polarization of the cell.
U.S. Pat. No. 3,264,618 issued to C. L. Wanlass et al. on Aug. 2, 1966, shows a four electrode ferroelectric memory element wherein an electric field can be applied either parallel or orthogonal to the polarization axis, the relation between the applied electric field and the polarization charge of the material being substantially a square hysteresis loop.
U.S. Pat. No. 3,381,611 issued to T. P. Foley on May 7, 1968 discloses an adjustable electromagnetic type slug holder wherein the strength of the magnetic field is adjusted to maintain a predetermined position. The magnetic lines of flux through the printing type provide the attraction force which is directly proportional to the amount of current in the winding.
U.S. Pat. No. 3,730,317 issued to R. L. Jaeschke on May 1, 1973 shows a magnetic coupling wherein energization of the coil to one polarity effects magnetization of the armature to an engaged position and energization of the coil to another polarity effects magnetization of the armature to a disengaged position.